Mechanical Behavior of Chopped Fiber-Reinforced Elastomeric Polyurea Foams

Abstract Elastomeric foams have received significant attention for impact mitigation in civilian and military applications. At the forefront of these materials are polyurea foams, which have demonstrated superior energy dissipation capabilities at reduced weight penalties under single- and repeated-impact loading over a wide range of projectile velocities. In this study, an innovative class of reinforced elastomeric polyurea foams is introduced by incorporating high-performance fibers, including Kevlar, Vectran, and Dyneema, into the foam slurry. A modified manufacturing process produced 30 cm × 30 cm foam sheets, from which cuboid specimens were extracted using an oscillating tangential knife. These specimens were subjected to quasi-static compression loading at a rate of 50 mm/min to 78% strain, and the testing accompanied by full-field digital image correlation to characterize deformation and strain localization. The results reveal a pronounced hygro-mechanical sensitivity in Kevlar-reinforced foams, which lessens their effective mechanical contribution. In contrast, Vectran- and Dyneema-reinforced foams exhibited substantial enhancements in mechanical response, including increases of more than 150% in the elastic modulus, 115% in plateau stress, and 70% in energy absorption, respectively, relative to the unreinforced baseline. These findings demonstrate the feasibility of tailoring the compressive response and energy-absorption characteristics of polyurea foams through chopped-fiber reinforcement, introducing a class of lightweight ballistic foams suitable for applications ranging from protective sports equipment to energy-absorbing components in armored systems and sandwich structures.